Skip-stitch mechanism for household sewing machines



W. WEISZ March 18, 1969 SKIP-STITCH MECHANISM FOR HOUSEHOLD SEWINGMACHINES Sheet Filed Sept. 29, 1967 INVEN'IIOR. wllllam Wensz i 1 lllnnnlli 1 Quad NEY ATT WITNESS:

SKIP-STITCH MECHANISM FOR HOUSEHOLD SEWING MACHINES W. WEISZ March 18,1969 Sheet Filed Sept. 29, 1967 R 2 w W m a m .l T H T M A March 18,1969 W. WElSZ SKIP-STITCH MECHANISM FOR HOUSEHOLD SEWING MACHINES SheetFiled Sept. 29, 1967 INVEN'IIOR. W|ll|um wens:

WITNESS:

March 13, 1969 w. WEISZ 3,433,189

SKIP-STITCH MECHANISM FOR HOUSEHOLD SEWING MACHINES Filed Sept, 29, 1967Sheet 4 of v INV N mR. WIIIIOm welsz WITNESS.- J? ma; waxy AT ORNEYMarch 18, 1969 w. WEISZ 3,433,189

SKIP-STITCH MECHANISM FOR HOUSEHOLD SEWING MACHINES Sheet 5 of 7 FiledSept. 29, 1967 Fig. 7 see 304 294 286 J5 n o2 INVENTOR. WIIIIOm Wensz BYwmusss: a, 'i WTEMEY W. WElSZ March 18, 1969 SKIP-STITCH MECHANISM FORHOUSEHOLD SEWING MACHINES Sheet Filed Sept. 29, 1967 INVENTOR. WnlhumWensz TTORNEY WITNESS: W056;

March 18, 1969 w. WEISZ SKIP STITCH MECHANISM FOR HOUSEHOLD SEWINGMACHINES Filed Sept. 29, 19s? Sheet of 7 v gINVEN'JIOR. wllham WenszWITNESS:

United States Patent 3,433,189 SKIP-STITCH MECHANISM FOR HOUSEHOLDSEWING MACHINES William Weisz, Rockaway, N.J., assignor to The Singergompany, New York, N.Y., a corporation of New ersey Filed Sept. 29,1967, Ser. No. 671,663

U.S. Cl. 112-158 12 Claims Int. Cl. D05b 3/02, 69/30 ABSTRACT OF THEDISCLOSURE A Zigzag sewing machine equipped With mechanism for joggingthe needle-bar to produce zigzag stitches and with cam actuatedskip-stitch mechanism separate and distinct from the needle-bar joggingmechanism, which provides for skipped-stitches by interrupting theendwise reciprocation of the needle-bar at predetermined intervalsdependent upon the contour of the cam or cams that actuate theskip-stitch mechanism.

Background of the invention In some of the prior art sewing mechanismscapable of skip-stitching the normal thread concatenation is preventedby utilizing various methods such as manipulation of the looper orneedle thread or by providing special needles or attachments in the bedof the sewing machine. In these prior art skip-stitch devices the needlepenetrates the work material during the skipping of the stitches whichresults in undesirable needle holes in all Work matcrial and prohibitsuse with some work fabrics in which such holes cannot be tolerated. Inaddition, the mechanisms utilized are either not sufficiently reliablefor modern, sophisticated household sewing machines, occupy too muchspace, or are inconvenient in that needles or attachments have to bechanged each time skip-stitches are required.

In other prior art sewing mechanisms capable of skipstitching thereciprocation of a needle-bar is interrupted to prevent formation ofstitches. In one such type of mechanism, one of two needle-bars mountedin the machine is manually disconnected to aid the operator in theproduction of square corners. The United States Patent No. 2,346,467,Apr. 11, 1944, Bills et al., discloses another needle-bar interruptingmechanism which, however, is built into an industrial type tuftingmachine that does not have zigzag stitching capability. The combinationof needle jogging motion with correlated needle-bar interruptions doesnot exist in the Bills et al. tufting machine. The Bills et al.needle-bar interrupting mechanism serves only for controlling thelocation of tuft formation and is continuously under the control of apermanently mounted cam, which mechanism cannot, therefore, readily becalled into and out of operation. Since the Bills et al. tufting machineis constructed so that reciprocation of the needlebar is continuouslyunder the control of the permanently mounted cam, it can be utilized foronly one type of stitching operation. In addition the Bills et a1.skip-stitch mechanism is bulky and occupies a large amount of spacerelative to the size of the machine.

Summary of the invention The present invention comprises needle-barinterrupting mechanism mounted in a sewing machine equipped with workfeeding apparatus that cooperates with the needle-bar in the formationof stitches. The interrupting mechanism is responsive to needle-barinterrupting program means operatively connected to actuating mechanismwhich in turn is operatively connected to the Work feeding apparatus.The needle-bar interrupting mechanism 3,433,189 Patented Mar. 18, 1969serves to interrupt the endwise reciprocation of the needlebar atpredetermined intervals dependent upon the construction of the programmeans. The present invention also provides mechanism for rendering theneedle-bar interrupting mechanism non-responsive t0 the program meansand either continuously effective or continuously ineffective.

The described embodiments of the present invention avoid the drawbacksof the prior art skip-stitch mechanisms briefly outlined above byplacing a relatively small and compact skip-stitch mechanism in anunused area of the sewing machine and by utilizing the existing patterncam shaft and the drive therefor. The skip-stitch mechanism of thepresent invention is reliable and does not require an exchange ofneedles or attachments when skipstitches are desired, and of course,since the skip-stitches are produced by interrupting the reciprocationof the needle-bar no undesirable perforations are made in the workmaterial during the skip-stitch mode of operation.

It is an object of this invention to provide an improved skip-stitchmechanism for a zigzag sewing machine.

It is another object of this invention to provide for an improvedmechanism for interrupting the vertical reciprocation of the sewingmachine at predetermined intervals.

It is still another object of this invention to provide for skip-stitchoperating mechanism separate and distinct from mechanism that operatesthe needle jogging mechanism both operating mechanisms being responsiveto cams mounted on the same cam shaft.

Having in mind the above and other objects that will be evident from anunderstanding of this disclosure, the invention comprises the devices,combinations and ar rangements of parts as illustrated in the presentlypreferred embodiments of the invention which are hereinafter set forthin such detail as to enable those skilled in the art readily tounderstand the function, operation, construction and advantages of itwhen read in conjunction with the accompanying drawings.

Brief description of the drawing FIG. 1 is a top plan view of oneembodiment of a zigzag sewing machine equipped with the skip-stitchmechanism of the present invention.

FIG. 2 is a perspective view of the head of the sewing machine shown inFIG. 1.

FIG. 3 is a perspective view of a portion of the zigzag and skip-stitchmechanism shown in FIG. 1.

FIG. 4 is a perspective view of the control mechanism shown in FIG. 3.

FIG. 5 is a vertical head-end view of the sewing machine in FIG. 1showing the needle-bar disengaged from the driving element.

FIG. 6 is a vertical head-end view of the sewing machine in FIG. 1showing the needle-bar connected to the driving element.

vFIG. 7 is a top plan view of another embodiment of a zigzag sewingmachine equipped with the skip-stitch mechanism of the presentinvention.

FIG. 8 is a skeletonized perspective view of the head end of the sewingmachine shown in FIG. 7.

FIG. 9 is an exploded perspective view of the control mechanism shown inFIG. 7.

FIG. 10 is a vertical head-end view of the sewing machine in FIG. 7showing the needle-bar connected to the driving elements.

FIG. 11 is a vertical head-end view of the sewing machine in FIG. 7showing the needle-bar disengaged from the driving elements.

FIG. 12 is an elevational View of the standard for the sewing machine inFIG. 1 broken away to show an ad ditional manual control for skip-stitchmechanism of the present invention.

FIG. 13 is a perspective view of part of the mechanism shown in FIG. 12.

Description of the preferred embodiment Referring more specifically tothe drawings, and first to FIGS. 1-6, the present invention isillustrated in the drawings as embodied in a sewing machine having azigzag mechanism that is herein illustrated and described only insofaras it is believed to be necessary for an understanding of thisinvention. Reference may be made to the United States Patents Nos.3,191,559, June 29, 1965, W. H. W. Marsh et al., and 2,862,468, Dec. 2,

- 1958, R. E. Johnson, for a more complete understanding of such azigzag mechanism.

With reference to the drawings, there is illustrated a zigzag sewingmachine having a frame 12 including a bracket arm 14, a head 16overhanging a bed 18, and a panel 20 in the front face of the bracketarm. Mounted in the head 16 is a presser-bar 17 that supports aconventional presser-foot 19 which overlays a feed dog 21. Conventionalfour motion feeding movement is imparted to the feed dog 21 by the usualmechanisms including a pair of eccentrics 23, 25 mounted for drivingengagement on a rotary arm shaft 15, which is journaled longitudinallyof the bracket arm 14, and eccentrics 23, 25 adapted to actuate pitmans31, 33, respectively. Also mounted in the head 16 for endwisereciprocation and for vibration laterally of the line of stitchformation, or in other words, for zigzag movements, is a needle-bar 22adapted to support a needle 24. Lateral vibration is imparted to theneedle-bar 20 by a bracket or gate 26 pivotally mounted at one end on astud 28 in the machine frame. The needle-bar 22 is journaled in aspherical bearing 27 in the bracket 26 and in a spherical hearing 29 inthe frame 16 and is thus free to partake of lateral jogging as well asendwise reciprocating movements. The bracket 26 is connected to one endof an endwise movable pitman 30, whereby upon actuation of the pitmanlateral vibration is imparted to the needle-bar. The opposite end of thepitman 30 carries a plate 32 pivotally mounted thereon by a pivot pin34.

The plate 32 and thus the pitman 30 and the needlebar mechanism arebiased toward the right, as seen in FIGS. 1 and 3, by a spring 35. Thereis also provided a spring 36 connected at one end to a plate 38 and atits other end to an arm 40 pivotally mounted in the frame 12 on a stud42, the feed end of which arm 40 abuts the plate 32 to resist overthrowthereof. The plate 32 is biased against a pair of cam followers 44, 46which are in turn biased into tracking engagement with any ones of thepattern cams 47 in a cam stack 48 to provide for actuation of the pitman30. The cam stack 48 is mounted for rotation on a vertical post 50 androtation is imparted thereto by a worm wheel 52 on the cam stack thatcooperates with a worm 54 on the rotary arm shaft 15.

The pitman 30 is adapted to be shifted to place the pivot pin 34alternatively substantially over the points of contact between the plate32 and the cam followers 44 and 46 or at points between these twopositions, thereby adjusting the amount of the cam-induced motion of thecam followers 44 and 46 that is transmitted to the plate 32 and thus tothe pitman 30 and the needle-bar mechanism. The means for shifting thepitman 30 comprises a lever 58 having a handle section 60 extendingthrough a slot in the panel 20 to be accessible to the operator.

The cam followers 44 and 46, respectively, are pivotally mounted andendwise slidable on vertical posts 62 and 64, respectively, which areparallel to the axis of the cam stack 48. The cam selector mechanism forthe cam followers 44 and 46 include two handles that protrude throughthe panel 20 to allow the operator to manipulate the cam followers tobring them into alignment with the necessary cams for the particule. i Qforming patterns desired. Reference may be made to the above citedpatents for a detailed explanation of the arrangement of the remainderof the cam selector mechanism.

Turning now to the mechanism that provides for the skip-stitchingfunction of the present invention, a counterweighted driving crank 70driven by the rotary arm shaft 15 is operatively connected to a flangedneedle-bar driving stud 72 by an arm 74. The crank 70 also drives aneedle thread take-up member 76 in the usual manner. The stud 72includes a flange 78 and a sleeve 80 adapted slidably to receive theneedle-bar 22. Without further connections therefor, verticalreciprocation of the stud 72 would not move the needle-bar 22 but wouldmerely slide up and down along the same.

In order to drive the needle-bar 22 in endwise reciprocation a block 82is secured to the upper section of the needle-bar and is formed with apair of spaced parallel cars 84 extending outwardly from the block 82toward the operator. The ears 84 support a pin 86 upon which ispivotally mounted, intermediate its ends, a latch finger 88 having anupper section 90 and a lower section 92. The lower section 92 is formedwith a hook-end 94 facing the needlebar which, as seen in FIG. 6, fitsbeneath the flange 78 when the driving stud 72 is moved up against theblock 82. A spring 96 serves to bias the latch finger 88 about the pin86 thereby constantly to urge the hook-end 94 inwardly toward theneedle-bar. One end section of the spring 96 is wrapped about the pin 86while the other end section engages the upper section 90 of the latchfinger 88. The free end segment of the upper section 90 is angledinwardly toward the needle-bar to form a flat angled surface 98 while atits extremity the upper section is turned outwardly, away from theoperator, to form a hook-end 100. The end of the needle-bar bracket orgate 26 is formed with a slabbed segment 102 against which the flatangled surface 98 of the latch finger 88 is pressed by an abutment arm104 which is preferably shaped like a paddle, into the needlebardisengaged position shown in FIG. 5. The abutment arm or paddle 104 issecured at one end to a horizontal rotatable shaft 106 journaled in thehead 16. The paddle 104 includes a shank 108 and an integrally formedblade 10 which extends at an obtuse angle from the shank. The blade 110is formed on its under surface with a notch 112 at the point where theblade meets the shank.

When the paddle shaft 106 is rotated to the position shown in FIG. 6,the paddle blade 110 clears the latch finger 88 to permit the latchfinger to rotate clockwise, as viewed in FIGS. 5 and 6, and then bringsthe hook-end 94 of the latch finger into the path of the driving stud 72which reciprocates as the rotary arm shaft 15 is rotated. As the stud 72moves upwardly along the needlebar the upper edge of the stud flange 78comes into contact with and slides along the inclined lower surface ofthe hook-end 94 and thereby pivots the hook-end away from the needle-barout of the path of the stud. The stud 72 continues along the needle-baruntil it lodges against the under surface of the block 82. At this pointthe lower edge of the flange 78 has cleared the hook-end 94 of the latchfinger and the bias exerted by the spring 96 rotates the hook-end towardthe needle-bar so that the ledge 114, formed at the hook-end slipsbeneath the lower edge of the flange 78 thereby to lock the driving stud72 between the block 82 and the hook-end of the latch finger. Since theblock is fixedly secured to the needle-bar the needle-bar will now bedriven in endwise reciprocation as the shaft 15 is rotated. The elements88 and 78 thus define latch means for coupling the needle-bar to theneedle-bar reciprocating means.

A plate 116 is secured to one wall of the head 16 and is formed at itsfree end with a narrow, vertical slot 118 which slidably receives ahorizontal stud 120 secured to and extending from the side of the block82. The slot 118 serves as a guide for the stud 120 thereby preventingthe needle-bar from rotating as it rcciprocates.

Assuming that the driving stud 72 is locked to the block 82, when thepaddle shaft 106 is rotated to the position shown in FIG. 5, the blade110 will intercept the upper section of the latch finger 88 as the latchfinger is driven upwardly by the block 82, which, in turn, is driven bythe driving stud 72. The force applied by the paddle blade 110 on theupper section of the latch finger is sufiicient to overcome the biasexerted by the spring 96 and rotate the latch finger counterclockwise,as viewed in FIGS. 5 and 6, thereby to move the hook-end 94 fromengagement with the under surface of the flange 78 and bring the fiatangled surface 98 of the upper section of the latch finger up againstthe fiat angled surface 102 of the bracket 26. The driving stud 72 isthereafter free to reciprocate along the needle-bar without driving theneedle-bar. The needle-bar is held in the elevated position shown inFIG. 5 because the force exerted by the paddle blade 110 on the uppersection of the latch finger 88 is sufficient to hold the finger againstthe needle-bar gate 26. Since the latch finger 88 is carried by theneedlebar, this prevents the needle-bar from continuing to reciprocatedue to the inertial forces generated when the needle-bar was beingdriven by the driving stud. It is noted that in the position shown inFIG. 5 the hook-end 100 of the upper section of the latch finger 88provides an auxiliary latch means which mates with the notch 112 in thepaddle blade 110 thereby adding an additional locking arrangementpreventing the needle-bar from continuing to reciprocate.

FIGS. 1, 3 and 4 should now be referred to as the description of themechanism that controls the locking and unlocking of the driving studwith the needle-bar unfolds below. As seen more clearly in FIG. 3 thepaddle shaft 106 is biased in a clockwise direction, as viewed in FIGS.5 and 6, by a spring 122 that is secured at one end to the inside wallof the frame 12 and at the other end to a stud 124 connected to andextending radially of a collar 126 which is secured to the standard-endsection of the shaft 106 by a lock screw 128. Between the collar 126 andthe sewing machine end wall there is mounted a thrust collar 130 securedto the paddle shaft 106 by a screw 132. The collar 130 in cooperationwith an enlarged section 134 of the shaft 106 serves to fix the axialposition of the shaft 106. The stud 124 is slidably received by slot 136formed in a horizontal ear 138 of a bell crank bracket 140 that ispivotally mounted on a pin 142 secured to a bracket 144 in turn securedto the inner wall of the frame 12. To the other end of the bell crankbracket 140 there is pivotally connected by a pin 146, an ear 148affixed to one end of a connecting rod 150 that extends toward thestandard end of the sewing machine, within the bracket arm.

The other end of the connecting rod 150 is also formed with an ear 152,which is pivotally connected by a pin 154 to a finger 156 of asubstantially fiat horizontally mounted cam follower lever 158. The camfollower lever 158 is formed with a finger 160 and a cam follower finger162. The finger 160 is pivotally mounted on a fulcrum pin 164 in turnreceived in the elbow section of a substantially fiat horizontallymounted and generally L- shaped manually influenced control lever 166.One leg 168 of the control lever 166 is pivotally mounted on a pin 170secured in a bracket 172 in turn secured to the rear inner wall of theframe of the machine. The other leg 174 of the control lever 166 isformed at its free end with an upstanding tab 176 that protrudes abovethe level of the cam follower lever 158. To the leg 174 is aflixed oneend of an angled fiat spring 180 to the other end of which is securedone end of a control lever arm 182 which protrudes through a horizontalelongated slot 184 formed in the panel 20. The elongated slot 184 hasformed in its upper wall three spaced slots labeled PSS (programmedskip-stitching), NS (nonstitching), and CS (conventional stitching),which state the three possible sewing machine modes into which thesewing machine may be placed. Since 180 is a spring the operator maypress down on the free end of the arm 182 and slide the arm along theslot 184 to any one of the notches at which point, simply by releasingthe arm, it will snap up into the notch and be held there againstfurther movement along the elongated slot.

The cam finger 162 of the cam follower lever 158 is vertically alignedwith a skip-stitch cam 186 which in the form illustrated in the drawingincludes four lobes and may be removed at any time from the cam stack 48and be replaced by other cams designed primarily for zigzag operation orby differently designed skip-stitch cams. The means for removablymounting the cam 186 on the cam stack 48 may utilize any of a number ofknown designs for removably mounting cams on cam stacks. The meansillustrated in the drawing is set forth in detail in the United StatesPatent No. 2,924,120, Feb. 9, 1960, Ralph E. Johnson, and includes acollar 188 integrally formed with and rising from the upper surface ofcam 186. The cam 186 may be removably locked to the vertical post 50 byutilizing a three pronged support spring 190 secured to the post 50 anda pin 192 received by an elongated hole 194 in the cam 186.

Turning now to the operation of the actuating and control elements shownin FIGS. 1, 3 and 4 the manner of operation will now be described whenthe control lever arm 182 is disposed in a first position in theprogrammed skip-stitching notch marked PSS as shown in FIG. 3. In thisposition of parts the positioning of the latch finger 88 is controlledby the cam 186. The cam follower finger 162 is shown in FIGS. 1 and 3 astracking the valley section of the cam 186 between two of the fourlobes. In such a position the spring 122 has urged the paddle shaft 186in a clockwise direction as viewed in FIG. 5 thereby bringing the paddleblade 110 into engagement with the upper section of the latch finger 88,as seen in FIG. 5, and disconnecting the hook-end 94 of the latch fingerfrom the needle-bar driving stud, leaving the stud free to reciprocateon the needle-bar, as explained above. With the paddle blade broughtinto contact with the upper section 90 which is in turn brought upagainst the rigid bracket 26 the paddle shaft 106 cannot rotate furtherin a clockwise direction (FIG. 5). The needle remains stationary, out ofwork material as seen in FIG. 5, for as long as the cam follower tracksthe surface of the valley of the cam 186. During this period of time,the feeding mechanism continues to move the work material beneath thepresser-foot 19 without any needle perforations being made or stitchesbeing formed in the work material. When the cam 186 has rotatedsufiiciently to bring the cam follower finger 162 to one of the lobesthe finger rides up the inclined surface thereof causing the camfollower member 158 to rotate on the pin 164 thereby to move theconnecting rod 150 to the right as viewed in FIGS. 1 and 3. Thismovement in turn causes the bell crank bracket to pivotcounterclockwise, as viewed in FIG. 3, through the intermediacy of theear 138, stud 124 and collar 126. As the paddle blade 110 is rotatedaway from the upper section 90 of the latch finger 88 to the positionshown in FIG. 6 the spring 96 urges the latch finger to rotate in aclockwise direction, as viewed in FIG. 6, bringing the head end 94 ofthe latch finger into the path of the needle-bar driving stud 72. As thestud 72 thereafter slides up the needle-bar, or if the timing is suchthat the stud is up as far as it will go, just as the latch finger isreleased the hook-end 94 slips under the flange 78 thereby to lock thestud to the needle-bar and drive the needle-bar in endwise reciprocationand allow the needle 24 to perforate the work material and bring theneedle thread into concatenation with the looper thread. The number ofstitches formed and the distance between each stitch or group ofstitches depends upon the length of the contacting surface of the lobesand the ratio of the speed of rotation of the rotary arm shaft 56 withthat of the cam stack. For purposes of illustration, the cam stack 48may rotate at a ratio of 24:1 with that of the rotary arm shaft 15 andeach of the four lobes on the cam 186 may be of such dimension as toallow the needle-bar to complete one cycle, resulting in a sewingfrequency of one work material penetration of the needle for every sixarm shaft revolutions. Thus, one stitch would be formed for every fiveskipped stitches.

When the control lever arm 182 is depressed by the operator and moved tothe next notch NS, the L-shaped hinge 166 pivots about the pin 170 andthe pivot point (represented by the pin 164) for the cam follower member158 is displaced along an arc toward the front Wall of the frame 12.This pulls the cam follower finger 162 just beyond the periphery of thelobes of the cam 186, but, since the cam follower member is pivoted onpins 164 and 154 the connecting rod 150 does not move appreciablyendwise. The spring 122 biases the paddle shaft sufficiently clockwise(FIG. to bring the paddle blade 110 into contact with the upper section90 of the latch finger 88 thereby to disconnect the needle-bar from theneedle-bar driving stud 72. The needle-bar remains disconnected from thedriving stud 72 while the control lever arm 182 is in the NS positionbecause the lobes of the cam 186 cannot actuate the cam follower finger162. This results in a period, of any duration desired during whichthere are no needle perforations and therefore no stitches formed.

When the control lever arm 182 is moved into the CS notch the sewingmachine operates in the conventional manner without any predeterminedskip-stitching. As the control lever arm 182 is moved from the NS to theCS position the L-shaped hinge 166 is again pivoted on pin 170 and, asseen in FIG. 4, the upstanding tab 176 of the hinge is brought intocontact with and applies a force to the finger 156 which causes the camfollower member 158 to pivot in a counterclockwise direction as viewedin FIGS. 1, 3 and 4, about the pin 164. Such movement of the member 158pulls the connecting rod 150 away from the head-end of the sewingmachine thereby to rotate the paddle blade 110 away from the uppersection 90 of the latch finger and permit the driving stud 72 to onceagain become locked to the needle-bar. So long as the control lever arm182 remains in the CS position the stud 76 will continue to drive theneedle-bar in endwise reciprocation.

In FIGS. 12 and 13 there is illustrated mechanism for a manual sewingcontrol which may be incorporated in the sewing machine shown in FIGS.1-6 which figures illustrate the first embodiment of the presentinvention.

As viewed in FIG. 12, the frame 12 of the sewing machine 10 includes ahollow standard 400 which rises from the bed 18. A vertical slot 402 iscut out of the edge of the front of the standard 400 between thestandard and the panel 20 which panel extends along the front of thebracket arm 14 (FIG. 1) and down along the front of the standard. Theslot 402 forms a recess that receives a handle 404 pivotally mounted bymeans of a screw 405 on one end section of a substantiall horizontalconnecting link 406 which link is in turn pivotally mounted at its otherend on a bracket 408 affixed to the frame of the machine. A frictionwasher 407 mounted on the screw 405 serves to hold the handle 404 in theraised position in the recess 402 when the handle 404 is not beingutilized. The handle 404 is formed at its pivotable end section with anabutment 409. The connecting link 406 is formed near the end that ispivotally connected to the handle 404 with a tab 411 that extendsoutwardly in a direction away from the front face of the standard 400 ashort distance which is sufiicient to intercept the abutment 409 of thehandle 404 when that handle is pivoted downwardly for a reason set forthbelow. To an intermediate point on the horizontal link 406 there ispivotally connected at one of its ends a substantially vertical leverarm 410 the other end of which is pivotally connected to one end of arock arm 412. The rock arm 412 is in turn secured at its other end to arock shaft 414 pivotally mounted in a bearing in the frame 12 andextends through the frame to the inside of the hollow standard 400.Clamped to the section of the rock shaft extending into the standard 400is a block 416 from which rises an integrally formed actuating arm 418.The cam follower member shown as 158 in FIGS. 1, 3 and 4, for thepurposes of this additional control, has integrally formed therewith adepending finger 420 positioned to intercept the actuating arm 418 whenthat arm is pivoted, as described below. A spring 422 mounted on therock shaft 414 serves to bias the rock arm 412 upwardly, as viewed inFIG. 12.

The handle 404 and the elements it serves to control provide theoperator with a manual means for at will engaging the needle-bar withthe drive therefor when the control lever arm 182 is in the NS ornonstitching position, thereby overriding the control lever arm in itsNS position. This control adds to the possible range of sewing that theoperator may perform by allowing her to make stitches of any lengthsimply by depressing and releasing the handle 404. Thus, for example,the operator may very conveniently obtain extremely long basting andblind hemming stitches.'The handle 404 is positioned on the standardclose to the area in which the operator is likely to be using her handsto manipulate the work material, thereby making it convenient for her todepress the handle 404. For additional convenience a removable elongatedhandle (not shown) may be connected to the handle 404 to bring theoperators control of the handle closer to the stitching area.

When the operator does not wish to make use of the manual sewing controlshe merely pushes the handle up into the slot 402 as illustrated by thedot-dash outline of the handle shown in FIG. 12 where it is held in thatposition by the friction washer 407. When the operator wishes to utilizethe manual sewing control she need mere- 1y place the control lever arm182 into the NS or nonstitching position and then grasp the handle 404and depress it to the ready position as shown in heavy outline in FIG.12. In this, the ready position, the manual sewing control is incondition for rapid actuation. Thus, when the operator depresses thehandle 404 the short distance required to bring the handle 404 to theposition shown in light outline, the needle-bar 22 is reconnected to theneedle-bar driving stub 72 and remains connected so long as the handle404 is held depressed against the bias of the spring 422. In this mannerthe operator may depress the handle 404 and quickly release it therebyto form a single stitch and thereafter move the work material anydistance she desires and then depress and quickly release the leveragain to form another stitch. Thus, the operator may form stitcheshaving any desired length therebetween without having to rely on thelength determined by the skip stitch cam.

In operation, when the handle 404 is depressed, and it is moved from itsvertical recessed position to the ready or intermediate position, itmerely pivots on the connecting link 406 until the abutment 409 isbrought into contact with the tab 411 on the connecting link 406.Because the abutment 409 and the tab 411 are in contact with each otherin the ready position, when the handle 404 is depressed further itcauses the conencting link 406 to pivot downwardly toward the bed :18.As the link 406 pivots downwardly it pulls the lever arm 410 downardlyand moves the rock arm 412 downwardly against the bias of the spring422. As the rock arm 412 moves downwardly it pivots the rock shaft 414clockwise (as viewed in FIG. 12) which in turn rocks the actuating arm418 clockwise (FIG. 12) from the position shown in heavy outline to theposition shown in light outline. As the actuating arm is pivotedclockwise it comes into contact with and pushes the depending finger 420to the right, as viewed in FIGS. 12 and 13, thereby to pivot the camfollower lever 158 to the right, as viewed in FIGS. 12 and 13. When thelever 158 is moved to the right it pulls the connecting rod 150 to theright also, thereby to connect the needle-bar 22 to the driving stud 72similarly as in the instance when the control lever arm .182 is moved tothe CS or conventional sewing position. When the handle 404 is released,the bias exerted by the spring 422 moves the manual sewing control backto the ready position thereby to once again disconnect the needle-barfrom the driving stud 72.

FIGS. 7-l1 disclose another embodiment of the present inventionincorporated in a zigzag sewing machine different from the machine inwhich the first embodiment is incorporated. The following is a briefdescription of the zigzag mechanism of this machine. For a more completedisclosure, reference may be made to United States Patent Nos.3,051,107, Aug. 28, 1962, R. E. Johnson, and 3,074,364, Ian. 22, 1963,R. E. Johnson et al.

A zigzag sewing machine 196 includes a frame 198 formed with a bed 200from which rises a standard (not shown) that carries a bracket arm 202that terminates in a head 204. Journaled longitudinally of the bracketarm 202 is a rotary shaft 206 that is driven by a motor (not shown)built into the standard.

In the head 204 there is a needle-bar gate 208 having a pair ofvertically spaced lugs 210 pivotally mounted on a vertical axis pivotrod 212 carried by bosses 214. The needle-bar gate has a pair ofvertically spaced lugs 216 in which a needle-bar 218 is mounted forendwise reciprocation. Endwise reciprocation is imparted to theneedle-bar 218 by a crank 220, on the head-end of the rotary shaft 206,which crank is connected by a link 222 to a needlebar driving block 224slidably mounted on the needle-bar, upon which block is mounted a latchfinger engaging stud 225 that extends parallel with the bed 200outwardly away from the needle-bar 218. The discussion below willexplain how the block 224 is connected to the needle-bar.

A needle 226 is secured upon the lower end of the needle-bar 218. Thetop of the bed 200 supports a throat plate 228 beneath the head 204which head also supports a presser-bar 230 that carries a pressure-foot232 that overlays a feed-dog 234 which is driven by mechanism (notshown) mounted in the bed 200.

A pitman 236 is arranged longitudinally of the bracket arm 202 and ispivotally connected to the needle-bar gate 208 by means of a bracket 238secured to the end of the pitman. Thus, upon endwise movement of thepitman 236 oscillation is imparted to the needle-bar gate 208, therebyimparting lateral vibration to the needle-bar 218. It is noted that theneedle-bar gate 208 is biased in a counterclockwise direction (as viewedfrom above the sewing machine) by a torsion spring 239 which is mountedon the vertical axis pivot rod 212 (FIGS. 10 and 11), thereby to urgethe pitman 236 to the left as viewed in FIG. 7.

Mounted in the bracket arm 202 is a vertical axis stud 240 on which isjournaled a tubular cam shaft having on the lower end thereof a wormwheel 244 which meshes with a worm 246 on the rotary shaft 206 to impartrotation to the cam shaft upon rotation of the rotary shaft. On theupper end of the cam shaft there is mounted a stitch pattern cam 248having a peripheral pattern surface that is tracked by a cam followerfinger 250 of pivotally mounted cam follower member 252. The cam 248 isreleasably clamped on the cam shaft by a screw 254. The cam followermember 252 is operatively connected to the pitman 236 so that the biasexerted by the torsion spring 239 through the needle-bar gate 208 to thepitman 236 also biases the cam follower finger into engagement with theperipheral pattern surface of the cam 248. Thus, upon rotation of thestitch pattern cam 248 oscillation is imparted to the cam followermember 252 which motion is transmitted to the pitman 236 whichreciprocates as a result thereof, thereby to impart lateral vibration tothe needle-bar gate 208.

Turning now to the construction and operation of the skip-stitchmechanism for the second embodiment of the present invention, a block256 (FIGS. 8, 10, 11) is fixedly secured to the top section of theneedle-bar 218 by a shoulder screw 258. Pivotally mounted on theunthreaded section of the shank of the shoulder screw 258 is a fiatlatch arm 260 which can be pivoted toward or away from the operator. Anotch 262 is formed in the arm 260- intermediate its ends and opens outaway from the operator. The notch 262 is adapted to receive the stud 225which is mounted in 'and protrudes outwardly from the block 224 in adirection away from the needlebar transversely of the direction of feed.A second notch 264 is formed in the latch arm 260 above the notch 262and also opens out away from the operator. Formed on the latch arm 260between the notches is a relatively short finger 266 that extends in adirection away from the operator. A flat spring 268, mounted by one endon the screw 258, the other end being adapted to engage the edge of thelatch arm 260 closest the operator, is tensioned so as to provide a biasthat urges the latch arm 260 in a clockwise direction (as seen in FIGS.8, 10, 11). The latch arm 260 includes a lower section formed as a guidefinger 270 having a flat guiding edge 272 that extends from the end ofthe latch arm to the notch 262.

Referring now to FIG. 7 a second cam, a skip-stitch cam 274 is mountedupon the tubular cam shaft 242 for rotation therewith beneath the stitchpattern cam 248. The cam 274 is formed on its periphery with threerelatively long lobes 273 divided by three relatively short notches 275.The skip-stitch cam 274 may be removed simply by removing the screw 254and the stitch pattern cam 248. A bell crank cam follower arm 276includes a leg 278 which is pivotally mounted upon a shouldered fulcrumscrew 280 which in turn threadedly engages a control lever 282intermediate the ends thereof. The control lever 282 includes a rear leg284, pivotally mounted at one end on a screw 286 that threadedly engagesa fixed shoulder extending from the inner rear wall of the frame .198,and a forward leg 288 secured to the other end section of the leg 284and extending through an elongated slot in the forward wall of the frame198. Secured to the top surface of the leg 288 is a spring element 292that also extends through the front wall of the frame 198. The elongatedslot is formed on its upper wall with three spaced notches labeled, fromleft to right, NS (non-stitching), CS (conventional stitching) and PS5(programmed skip-stitching) A bell crank lever 294 is also pivoted onscrew 286 at the juncture of lever legs 296 and 298. Lever legs 296 and298 support upstanding pins 300 and 302, respectively. The bell crankcam follower arm 276 is also formed with a leg 304 which includes nearits free end section a slot 306 and at its free end a lip 308. It isnoted at this point that the control arm 282 and the bell crank lever294 could be combined into a one piece unit which Would function in thesame manner as the described lever and arm. The slot 306 receives a pin310 secured to a collar 312 afiixed to a rock shaft 314 mountedlongitudinally of the bracket arm 202 beneath the leg 304. The rockshaft 314 extends into the head 204 and has affixed to the head end adepending flat actuating abutment arm 316 which is formed at its freeend with a short pin 318 that extends parallel to the bed 200. A spring320 is connected at one end to the leg 304 and at the other end to afixed stud 322, thereby biasing the cam follower arm 276 in acounterclockwise direction, as viewed from above the sewing machine, tourge a pin 324 mounted on the free end of the leg 278 into engagementwith the periphery of the skip-stitch cam 274.

In operation, movement of the operator influenced control lever 282along the slot 290 to the right and into the notch labeled PSS in FIG. 9shifts the machine into the programmed skip-stitch mode. In thisposition the shouldered fulcrum screw 280 will be located so as toposition the cam follower lever 276 with the cam follower pin 324 inengagement with the periphery of the skip-stitch cam 274 and the slot306 in the cam follower lever 276 in position to control the pin 310 andthe associated rock shaft 314 and abutment arm 316 from theskip-stitching position illustrated in FIG. 11 to the sewing positionillustrated in FIG. in response to the conformation of the skip-stitchcam 274.

With the cam follower pin 324 in tracking engagement with the peripheryof the skip-stitch cam 274 the sewing machine is ready to produceprogrammed skip-stitch sewing simultaneously with the zigzag sewing thatis controlled by the zigzag apparatus described above. As the cam 274rotates and the cam follower pin slides along one of the lobes, as shownin FIGS. 7 and 9, the latch arm 260 remains disengaged from the drivingblock 224. When the cam rotates to the point where the cam follower pin324 comes abreast of one of the notches 275 the bias exerted by thespring 320 forces the pin 324 into the notch 275 thereby pivoting thecam follower arm in a counterclockwise direction. The counterclockwisemovement of the cam follower arm is sufiicient to rotate the actuatingabutment arm 316 far enough in a clockwise direction, as viewed in FIG.10, to remove the pin 318 of the actuating abutment arm 316 fromengagement with the latch arm 260. This permits the latch arm 260 toswing in a clockwise direction, as viewed in FIG. 10, whereby as theblock 224 is driven upwardly the stud 225 engages the notch 262 and theneedle-bar is again locked to the driving block 224 by the bias exertedby the spring 268. Each of the cam notches 275 is just long enough topermit one reciprocation of the needlebar resulting in the formation ofone stitch. The lobe lengths are designed to provide for five skippedstitches, the arm shaft to cam shaft ratio being 18:1, but of courseother combinations of stitches to skipped stitches may be provided bydifferently designed cams.

As the cam rotates further to bring the cam follower pin 324 onto thefollowing lobes 273 the actuating abutment arm 316 is pivotedcounterclockwise (FIG. ll) which pivots the latch arm counterclockwiseaway from the stud 225, thereby once again disconnecting the drivingblock from the needlebar resulting in skipped stitches. It is noted thatthe guide finger 270 at the lower section of the latch arm is longenough to prevent the stud 225 from dropping below the end of the fingerat the lowest point in the reciprocation of the driving block 224. Thus,the latch arm is prevented from swinging in a clockwise direction, asviewed in FIGS. 8, 10 or 11, to the other side of the path of travel ofpin 225.

After the needle-bar is disconnected it ends to continue reciprocatingfor a short time due to inertial forces, resulting in further undesiredperforations and stitches. The notch 264 was formed in the latch arm, atthe point where the pin 318 of the actuating arm contacts the latch arm,to obviate this problem. Thus, when the notch 264 is engaged by the pin318 the effect is, in cooperation with the bias exerted by the spring268, to lock the latch arm to the actuating arm 316 thereby holding theneedlebar in a raised positioin against the existing inertial forcestending to continue the reciprocation of the needle-bar after it isdisconnected.

When the control handle is shifted into the position shown in FIGS. 7and 9 and marked CS, the skip-stitching mechanism will be inoperativeand the sewing machine will perform continuous stitching. Suchcontinuous stitching is made possible by a shift of the shoulderedfulcrum pin 280 which will position the slot 306 in the cam followerlever so as to maintain the pin 310, the associated rock shaft 314 andthus the abutment arm 316 continuously out of engagement with the latcharm 260.

When the control lever 282 is moved all the way to the left, as viewedfrom the front of the sewing machine, into the notch labeled NS themachine is shifted to the nonstitching mode, where the needle-bar isprevented from reciprocating during the entire period that the lever isin that position. When the control lever is moved to the NS position itpivots about the screw 286 in a clockwise direction, as viewed fromaobve, carrying the shouldered fulcrum screw 280 along a slight arc inthe general direction of the head 204. In addition the edge 326 of therear leg 284 of the control lever is brought up against the pin 302 ofthe bell crank 294, thus, as the control lever is rotated the bell crankis also rotated in the clockwise direction bringing the pin 300 at theother end of the crank up against the lip 308, which upon furtherrotation of the control lever causes the cam follower arm 276 to pivotin a clockwise direction as viewed in FIG. 7. The clockwise movement ofthe arm 276 rocks the shaft 314 sufliciently far in the counterclockwisedirection, as viewed in FIG. 11, to disconnect the needle-bar andprevent the formation of stitches, so long as the control lever is inthe NS position.

It is noted that the skip stitch cams merely control the interruption inthe vertical reciprocation of the needle-bar 22 while the other cams inthe cam stack serve to control the zigzag motion or lack of the same.Thus, many different stitch patterns can be obtained by either changingthe skip-stitch cams or adjusting the other sewing machine stitchpattern controls or by combinations of the same.

Having thus set forth the nature of this invention, what I claim hereinis:

1. A skip-stitch mechanism for a zigzag sewing machine having a frame,actuating mechanism in said frame, a needle-bar gate shiftably supportedfor lateral jogging movement in said frame, a needle-bar carried in saidgate for laterally jogging movement therewith and for endwisereciprocatory movement relatively thereto, needle-bar reciprocatingmeans driven by said actuating mechanism and including coupling meansseparable to effect interruption of endwise reciprocatory movement ofsaid needle-bar, needle-bar interrupting program means driven by saidactuating mechanism, and means carried by said sewing machine frame andresponsive to said program means for effecting separation of saidcoupling means in any lateral position of said needle-bar gate.

2. A skip-stitch mechanism for a sewing machine as set forth in claim 1including means for selectively rendering said means for effectingseparation of said coupling means nonresponsive to said needle-barinterrupting program means, said means for selectively rendering saidmeans for effecting separation of said coupling means nonresponsive tosaid needle-bar interrupting program means including means for providingtwo distinct positions of nonresponse of said coupling means to saidneedle-bar interrupting program means, a first position of nonresponsein which said means for effecting separation of said coupling means iscontinuously operative and a second position of nonresponse in whichsaid means for effecting separation of said coupling means iscontinuously inoperative.

3. A skip-stitch mechanism for a sewing machine as set forth in claim 2wherein said selectively rendering means includes a first and a secondoperator-influenced mechanism, each of which mechanism is actuable bythe operator to shift the means for effecting separation of the couplingmeans from said first position of nonresponse to said second position ofnonresponse, said first mechanism being positioned on said sewingmachine frame in a more convenient location for operator actuation thansaid second mechanism.

4. A skip-stitch mechanism for a sewing machine as set forth in claim 3including spring means for biasing said first operator-influencedmechanism toward said first position from said second position when saidfirst operator influenced mechanism is deactuated.

5. A skip-stitch mechanism for a sewing machine as set forth in claim 1in which said coupling means includes cooperating latch means on saidneedle-bar reciprocating means and on said needle-bar, and in which saidmeans for separating said coupling means includes an abutment armcarried on said sewing machine frame and having an effective position inthe path of said latch means on said needle-bar.

6. A skip-stitch mechanism as set forth in claim 1 including needle-barholding means automatically effective upon separation of said couplingmeans for maintaining said needle-bar in a predetermined fixed endwiseposition in said needle-bar gate.

7. A skip-stitch mechanism as set forth in claim 6 in which saidneedle-bar holding means comprises auxiliary latch means carried on saidneedle-bar and on said abutment arm, said auxiliary latch means havingcooperative engaging relationship when said abutment arm occupies saideffective position.

8. A sewing machine having a frame, work feeding mechanism carried insaid frame, a needle-bar supported in said frame for endwisereciprocatory and lateral jogging movements, actuating means in saidframe for said work feeding mechanism and said needle-bar in said frame,means driven by said actuating means for imparting endwise reciprocationto said needle-bar, a plurality of cam means each driven by saidactuating means in timed relation one to another, means responsive toone of said cam means for jogging said needle-bar transversely of thedirection of endwise reciprocation of the needle-bar to provide for theproduction of zigzag stitches, means for interrupting the endwisereciprocation of said needle-bar at predetermined intervals, meansseparate and distinct from said needle-bar jogging means and responsiveto the other of said cam means for effecting operation of saidneedle-bar interrupting means, and means effective during operation ofsaid work feed mechanism by said actuating means for selectivelyrenedring said needle-bar interrupting means nonresponsive to the saidother of said cam means.

9. A sewing machine as set forth in claim 8 in which a cam shaft isjournaled in said sewing machine frame and operatively connected withsaid actuating mechanism and in which said plurality of cam means iscarried coaxially on said cam shaft.

10. A sewing machine as set forth in claim 8 wherein said means forselectively rendering said needle-bar interrupting means nonresponsiveto said cam means includes means for providing for two distinctpositions of nonresponse, one in which said needle-bar interruptingmeans is continuously operative and another in which said needlebarinterrupting means is continuously inoperative.

11. A sewing machine as set forth in claim 10 including manuallyoperated means for at will overriding said means for providing for twodistinct positions of nonresponse when said last named means is in thecontinuously operative position of nonresponse and placing saidneedlebar interrupting means in the continuously inoperative position.

12. A sewing machine as set forth in claim 10 in which said means foreffecting operation of said needle-bar inter rupting means includes acam follower lever, linkage interconnecting said cam follower lever withsaid needle-bar interrupting means, a manually influenced control lever,a pivotal support for said control lever relatively to said sewingmachine frame, fulcrum means for said cam follower lever carried by saidcontrol lever in spaced relation to the pivotal support for said controllever, means defining a first position of said control lever locatingsaid fulcrum means to provide for tracking of the other of said cammeans by said cam follower lever and response of said needle-barinterrupting means to said cam means, means defining a second positionof said control lever relocating said fulcrum means to provide for oneof said positions of nonresponse to said cam means, and means engageablewith said cam follower lever and influenced by movement of said controllever into a third position to provide for the other of said positionsof nonresponse to said cam means.

References Cited UNITED STATES PATENTS 2,318,200 5/1943 Cobble et a1112-221 X 2,333,689 11/1943 Sigoda 112---2.21 X 2,346,467 4/ 1944 Bills112-221 X RICHARD J. SCANLAN, 1a., Primary Examiner.

US. Cl. X.R. 112-221

